The USN is testing big rail guns near here. You hear some weird kabooms offshore occasionally. And then there's the stuff that falls back into the ocean from NASA Wallops rocket launches... don't touch the Martians!

The interesting thing is that railguns use Godawful amounts of electrical power, so the issue becomes one of being able to store enough electricity, and then to get enough kWh to the rail gun fast enough. It requires huge copper wires as big around as your leg, and they actually thrash like fire hoses when the gun goes off, due to all the electricity passing through them!

I hear they can get projectiles up to something like MACH 10, more than double the MV of the fastest rifle cartridges.

I first heard 'talk' of rail guns as far back as in the mid-80's in the Corps. It was like hearing or reading some far-fetched future technology that would've been on the cover of Popular Mechanics back in those days!